Germination characteristics of Artemisia ordosica (Asteraceae) in relation to ecological restoration in northern China

2005 ◽  
Vol 83 (8) ◽  
pp. 1021-1028 ◽  
Author(s):  
Yuanrun Zheng ◽  
Glyn M Rimmington ◽  
Yong Gao ◽  
Lianhe Jiang ◽  
Xuerong Xing ◽  
...  

Artemisia ordosica Krasch. (Asteraceae) is the dominant psammophytic shrub species on the Ordos Plateau of northern China and is used for revegetation of semi-arid areas. Experiments were conducted to determine the effects of light intensity, constant temperature, alternating temperatures, and water potential on germination to determine why air-dispersed achenes fail to germinate well in the field. Achenes germinated within a wide alternating temperature window, except under the 5:15 °C (night:day) temperature regime in darkness. Final percent germination (FPG) was higher in darkness than in light at alternating temperature regimes, except under the 20:30 °C (night:day) temperature regime. Achenes subjected to a range of constant temperatures in the dark had high FPG over 76.8% except at 30 °C (8%). Photosynthetic photon flux densities (PPFD) of 100 and 400 µmol·m–2·s–1 significantly lowered FPG under a 10:20 °C (night:day) regime, while at 0–25 µmol·m–2·s–1 PPFD, the FPG was over 92%. Few achenes germinated at –1.4 MPa. The most suitable temperature for germination of achenes placed under water stress was 20 °C. The best timing for air dispersal is mid-May, so seeds would become covered with sand at a time when temperature and soil moisture conditions were optimal for germination.Key words: air dispersal, Artemisia ordosica, hydrothermal time, psammophytes, semi-arid regions, temperature.

2004 ◽  
Vol 82 (11) ◽  
pp. 1662-1670 ◽  
Author(s):  
Yuanrun Zheng ◽  
Yong Gao ◽  
Ping An ◽  
Hideyuki Shimizu ◽  
Glyn M Rimmington

Agriophyllum squarrosum (L.) Moq. (Chenopodiaceae), a pioneer species of natural succession in semi-arid regions of China, is widely used for vegetation rehabilitation by air seeding. Experiments were conducted to determine the effects of light intensity and photoperiod, as well as constant and alternating temperatures, on germination to improve the technology of air seeding. Seed of A. squarrosum rarely (<18.5%) germinated at 5/15, 10/20, 15/25, and 20/30 °C (night/day); 39.5% of seeds germinated at 25/35 °C in a 14-h (215 µmol·m–2·s–1) photoperiod. Under dark conditions there was a high final percent seed germination (>90%), except for 71.8% final percent seed germination at 5/15 °C. Constant temperature conditions were associated with lower seed germination (<50%). Less than 13% of seeds germinated at different light intensities (25–400 µmol·m–2·s–1) at 10/20 °C. There was no significant difference in final percent germination when seeds were exposed to 400, 100, or 25 µmol m–2 s–1 for 2 h daily. Final percent germination and germination rate deceased rapidly when the photoperiod was increased under 400 µmol·m–2·s–1. Only 49.2% of seeds germinated after 3 d. Because of the deleterious effect of light on germination, air seeding in late May is recommended.Key words: Agriophyllum squarrosum, air seeding, alternating temperature, constant temperature, light, semi-arid regions.


2016 ◽  
Vol 96 (3) ◽  
pp. 321-328
Author(s):  
Michael E. Foley

Germinability of dormant seeds or the capacity to germinate under particular conditions is sometimes enhanced by a diurnal alternating temperature regime relative to a constant temperature. Alternating temperature regimes vary in amplitude (difference between the minimum and maximum) and midpoint (average). The aim of this research was to test the effects of amplitude and midpoint regimes on germination of dormant leafy spurge seed from a Fargo, ND population in water and gibberellic acid (GA3). The optimal regimes for germination in both water and GA3 were 20:30 °C (16 h:8 h) and 20:35 °C (19 h:5 h), which provided amplitudes of 10 °C and 15 °C, respectively, with both conditions having a midpoint temperature of 23.3 °C. However, midpoint temperature of 22 °C to 27 °C were equally effective for germination under the 20:30 °C and 20:35 °C alternating temperature regimes. Additional alternating temperature regimes with amplitudes of 15 °C (15:30 °C and 10:25 °C), 20 °C (10:30 °C), and 25 °C (10:35 °C) generally displayed reduced germination in both water and GA3, which is likely attributable to the low initial alternating temperature (≤15 °C) component of the regime relative to the higher initial temperature of 20 °C for the optimum regimes of 20:30 °C and 20:35 °C. Under the alternating temperature regimes tested, seeds germinated in GA3 generally displayed higher germination (≥80%) compared with seeds in water (30%–50%).


Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 847-852 ◽  
Author(s):  
Rosangela Picciau ◽  
Marco Porceddu ◽  
Gianluigi Bacchetta

Each plant species has particular requirements for seed germination, and some of them respond differently to constant or alternating temperature regimes. In this study, the interchangeable effects of different treatments and temperatures on the completion of seed germination of Clematis vitalba L. were investigated. The seeds were tested with a constant (from 5 °C to 25 °C) or a fluctuating (25/10 °C) temperature regime, and the effect of gibberellic acid (GA3), incubation at warm (W) or cold (C) temperatures while being imbibed, and drying after ripening (DAR) were evaluated. The final germination percentages and the time in days required to reach 50% of germination (T50) were calculated. GA3 and C significantly enhanced completion of seed germination at all of the temperatures tested. A strong positive effect of alternating temperature was observed, which triggered completion of seed germination regardless of treatment. Under the fluctuating temperature, the chilled seeds had the most rapid germination. Low germination rates were observed for both control and DAR treatments. Seeds of C. vitalba display a certain degree of dormancy, which can be broken by moist chilling and GA3 treatments. Moreover, alternating temperature stimulates the completion of seed germination by satisfying certain physiological requirements for germination under constant temperatures.


Agronomy ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 173 ◽  
Author(s):  
Ya Liu ◽  
Xiuxia Ren ◽  
Hai Jeong ◽  
Hao Wei ◽  
Byoung Jeong

Adenophora triphylla (Thunb.) A.DC., three-leaf lady bell, is an important medicinal plant used against cancers and obesity. It has been well-established that the temperature regime affects plant growth and development in many ways. However, there is no study available correlating the growth of A. triphylla seedlings with different day and night temperature regimes. In order to find an optimal temperature regime, growth and physiology were investigated in A. triphylla plug seedlings grown in environment-controlled chambers at different day and night temperatures: 20/20 °C (day/night) (TA), 25/15 °C (TB), and 20/15 °C (TC). The seedlings in plug trays were grown under a light intensity of 150 μmol·m−2·s−1 PPFD (photosynthetic photon flux density) provided by white LEDs, a 70% relative humidity, and a 16 h (day)/8 h (night) photoperiod for six weeks. The results showed that the stem diameter, number of roots, and biomass were significantly larger for seedlings in TB than those in TA or TC. Moreover, the contents of total flavonoid, total phenol, and soluble sugar in seedlings grown in TB were markedly higher than those in seedlings in the other two treatments. Soluble protein content was the lowest in seedlings in TC, while starch content was the lowest in seedlings grown in TA. Furthermore, seedlings grown in TB showed significantly lower activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase. Native PAGE (polyacrylamide gel electrophoresis) analysis further proved low activities of antioxidant isozymes in TB treatment. Meanwhile, the lowest content of hydrogen peroxide was observed in seedlings grown in TB. In conclusion, the results suggested that the 25/15 °C (day/night) temperature regime is the most suitable for the growth and physiological development of A. triphylla seedlings.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1367
Author(s):  
Valentina Obradović ◽  
Jurislav Babić ◽  
Verica Dragović-Uzelac ◽  
Antun Jozinović ◽  
Đurđica Ačkar ◽  
...  

The objective of this research was to investigate the potentiality of carrot powder (CP) utilization at levels 4, 6, or 8% as ingredient of corn snacks and evaluation of the extrusion influence on functionally important ingredients such as carotenoids (color), polyphenols, fiber, fat, and antioxidant activity. The influence of ascorbic acid (AA) as an external source at levels 0.5 and 1% on this particular extrusion was also investigated. A single-screw extruder at two temperature regimes (135/170/170 °C (E1) and 100/150/150 °C (E2)) carried out extrusion. The E1 temperature regime acted favorably on total polyphenol content and crude fiber, but fat preferred the E2 regime. Extrusion, especially the E1 temperature regime, increased the extractability of carotenoids. Ascorbic acid degraded during extrusion, but it still provided protection to carotenoids and color attributes of extrudates. Snacks with increased nutritional and functional value due to carrot powder addition were successfully produced, which is a starting point for production of a new type of extruded snacks.


2008 ◽  
Vol 311 (1-2) ◽  
pp. 19-28 ◽  
Author(s):  
Naili Zhang ◽  
Shiqiang Wan ◽  
Linghao Li ◽  
Jie Bi ◽  
Mingming Zhao ◽  
...  

PLoS ONE ◽  
2018 ◽  
Vol 13 (8) ◽  
pp. e0198750 ◽  
Author(s):  
Yige Bao ◽  
Xinying Zhou ◽  
Hanbin Liu ◽  
Songmei Hu ◽  
Keliang Zhao ◽  
...  

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.


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